1. Field of the Invention
The present invention relates to a method for the production of bright or cold-drawn steel, particularly bar-shaped bright round steel produced from hot-rolled steel.
2. Description of the Related Art
Bright steel, particularly bright round steel, is a rolled or wrought bar steel with a metallically bright surface. Surface quality is usually divided into technical quality classes which are determined by allowable dimension tolerances, e.g. according to German Industrial Standard DIN 668 corresponding to International Standard (JSO Tolerance group h11 ). The metallically bright surface of the steel is conventionally produced by means of peeling or bright-drawing. Bright-drawing is a process for the production of drawn steel in which the oxide film on the surface is removed and a non-cutting cold forming is affected. Stands suited for this method are drawing rolling mills in which a coiled rolling material is drawn through the non-driven rolls of a roll stand. Drawing benches, which are outfitted with correspondingly shaped drawing tools are also known as suitable machine tools for the production of bright steel.
The peeling of the round steel for producing a bright surface is a cutting process and is affected on so-called peeling machines which are outfitted with correspondingly shaped peeling knives and with guiding and driving rolls. Peeling of the round steel is a step which always involves material loss, even with steel qualities which have not undergone any surface decarburization of the skin and thus need not, necessarily, be treated by material removal.
The investment costs for a drawing rolling mill, a drawing bench, or a peeling machine are high, as are the continuous tooling costs for scalping knives, guide and driving rolls, etc. In addition, there is the fact that the discontinuous operation in drawing and the requirements of devices arranged upstream and downstream make it difficult to incorporate the aforementioned processing machinery in the layout of production-line finishing.